import numpy as np
A=np.array([[1,2],[3,4]])
print(A.shape)
print("------------")
B=np.array([[5,6],[7,8]])
print(np.dot(A,B))
print("------------")
print(A.dot(B))
print("------------")
A=np.array([[1,2,3],[4,5,6]])
A=np.array([[1,2],[3,4],[5,6]])
print(np.dot(A,B))
print("------------")

A=np.array([[1,2],[3,4],[5,6]])#(3,2)
B=np.array([7,8])#array可以灵活变换，不需要写成[[7],[8]]
print(np.dot(A,B))#(3,1)